I'm in the repair category. Especially for things like power supplies. They are very repairable and they will be very reliable after they are done. Probably even more reliable than the new power supplies when it comes to the high voltage section.

For a WMS WPC 89 and later CPU, if it is corrosion damaged and a mess it makes sense to buy new. If the only problem is U20 being out, repair it. DE CPUs are worth repairing as are System 11. WMS driver boards are pricey and repair often makes sense.

Of course each board and every person's situation is its own unique case, and you can't make a blanket statement that everything should be repaired or you should always buy new.